Method and apparatus for detecting parameters of a liquid metal in a container
A method and an apparatus for measuring simultaneously and in a reliable manner both the level of molten metal in a casting mold and the depth of molding powder floating over the molten metal, wherein an electromagnetic open cavity is formed on the upper inlet aperture of a casting mold and electromagnetic signals are introduced into the cavity by means of an emitting device. The electromagnetic signals exiting the cavity are then detected and a relationship is established between the detected properties of the electromagnetic cavity and the level of molten metal and depth of molding powder.
Latest Fondazione Torino Wireless Patents:
- Pruning methods for the generation of S-random interleavers, and interleaver performing the methods
- System and method for estimating mobile wireless unit position in a localized area
- Suspension system for a wheeled vehicle and a wheeled vehicle equipped with such a suspension system
- Electromechanical driving and braking module for a wheeled vehicle and a wheeled vehicle equipped with such an electromechanical module
- Electromechanical actuating device for a wheel brake system of a motor vehicle and a brake system equipped with such an actuating device
This application claims the priority of European patent application no. EP 05012031.0, filed Jun. 3, 2005.
BACKGROUNDThe present invention relates to a method and an apparatus for detecting and/or measuring predefined parameters of a liquid metal in a container. In particular, the present invention relates to a method and an apparatus for detecting the depth of mold powder in a casting mold and the level of liquid metal in said casting mold.
In
In a continuous casting process, known in the art and carried out by means of an apparatus as depicted in
In a continuous casting process carried out by means of a prior art apparatus as depicted in
Several methods and apparatuses have been proposed over the years for the purpose of measuring the depth of molding powder and the level of molten metal in a casting mold. For instance, European patent application no. EP0658747 discloses a continuous casting mold comprising means for gauging the level of molten metal in the mold so that it can be maintained near the top of the mold without overflowing. The known measuring device comprises a radioactive source on one side of the mold and a scintillation crystal detector on the opposite side of the mold. The radioactive source is a continuously disintegrating material, which permits particles/energy in the form of α, β, and γ rays in transmuting to a lighter, elemental material. The detector is responsive to the impingement of these particles/energy to provide a given signal level which is inversely proportionate to the square of the distance between the source and the detector. The intensity of the radiation impinging on the detector and the output signal therefrom, is inversely proportional to the degree to which molten metal absorbs radiation, which in turn is a function of the level of the molten metal in the mold. Means are also disclosed in the above identified European patent application for gauging the level of molten metal in the mold as a function of the level of molten metal detected in the tube.
A further solution for measuring the level of molten metal in a continuous casting mold is known from European patent application EP0859223. In particular, the apparatus for detecting the level of liquid metal within the mold disclosed in this patent application includes an array of radiation detectors positioned to one side of the mold and extending to positions above and below the expected height of liquid metal. Moreover, a source of radiation photons is positioned on the mold side opposite to that on which the detector array is positioned, and means are provided for counting the number of incident photons received by each radiation detector or neighboring detectors in unit time. The number of incident photons received provides a measure of the height of liquid metal within the mold. Signals representative of the measures of liquid metal height may therefore be employed as control signals for controlling automatically or periodically the level of liquid metal inside the mold.
According to a further prior art method for detecting and/or measuring the level of liquid metal in a casting mold an inductive device is used, adapted to excite parasite electrical currents in the molten metal so that the level of liquid metal within the mold may be detected as a function of the power dissipated by the system.
According to still a further solution known in the art, the temperature of the walls of the mold is measured and the level of molten metal in the mold is detected computed as a function of the temperature measured.
The methods and/or apparatuses known in the art are affected by several drawbacks. In particular, the most relevant problem affecting the prior art measuring apparatuses and/or methods relates to the fact that these methods and/or apparatuses do not allow the simultaneous, reliable detection of both the level of molten metal and the depth of molding powder. In particular, since it is not possible, with the known methods and apparatuses, to distinguish between the depth of molding powder and the real level of molten metal, the values measured may not be used for gauging in a reliable manner these two parameters. This is due, in particular, to the fact that the values measured only give an indication of the total level of the material inside the mold (molten metal and molding powder) but do not allow one to obtain reliable measures of these two parameters simultaneously. In other words, the measured values only give an indication of the total level of material contained in the mold, this total level arising from both the level of molten metal and the depth of molding powder.
Accordingly, it would be desirable to provide a measuring method and apparatus allowing one to overcome the drawbacks affecting the prior art methods and/or apparatuses. Moreover, it would be desirable to provide a method and apparatus for measuring both the level of molten metal and the depth of molding powder in a casting mold, allowing detection these two parameters in a reliable manner. It would likewise be desirable to provide a measuring method and apparatus allowing measurement of these two parameters simultaneously without requiring expensive and big computing equipment. It would further be desirable to provide a measuring method and apparatus adapted to be used in combination with several of the known casting processes and systems.
SUMMARYIn one method and apparatus for measuring the depth of mold powder in a casting mold and the level of liquid metal in said casting mold, an electromagnetic open cavity is formed on the liquid metal and the depth of mold powder and the level of liquid metal are detected measured as a function of the electromagnetic behavior of the cavity. Still in more detail, the curve of resonance of the electromagnetic open cavity is detected and the depth of molding powder and the level of liquid metal are measured as a function of the bandwidth of the curve and the frequency of resonance of the electromagnetic open cavity.
Because in this method and apparatus, the depth of molding powder and the level of molten metal in the mold are measured simultaneously, it is also possible to gauge control during the casting process, both the depth of molding powder and the level of molten metal in the mold.
In another embodiment, a measuring device is provided for measuring predefined parameters of a liquid metal in a container, the container comprising an inlet aperture through which the liquid metal is introduced into the container, characterized in that the measuring device is adapted to be placed on said inlet aperture of said container so as to form, in combination with the container, an electromagnetic open cavity, and in that said measuring device comprises detecting means adapted to detect the electromagnetic behavior of the cavity so as to obtain said predefined parameters as a function of the electromagnetic behavior.
In another embodiment, a casting apparatus is provided for use in a continuous casting process, wherein the apparatus comprises a casting container with an inlet aperture for receiving liquid metal and an outlet aperture for discharging solidified metal. The container is adapted to contain a predefined amount of liquid metal. The apparatus is equipped with a measuring device. The measuring device is placed on the inlet aperture so as to form, in combination with the container and the liquid metal contained therein, an electromagnetic open cavity.
In another embodiment, a method is provided for measuring predefined parameters of a liquid molten metal in a container, wherein the container comprises an inlet aperture through which the liquid metal is introduced into the container. In the method, the steps are performed of forming an electromagnetic open cavity above the liquid metal, detecting the electromagnetic behavior of the cavity, and obtaining the predefined parameters as a function of said electromagnetic behavior.
In another continuous casting process, liquid metal is introduced into a continuous casting mold, and solidified metal is extracted from the mold. The process includes measuring predefined parameters of the liquid metal in the mold.
The embodiments provided herein employ the realization of an electromagnetic open cavity above the liquid metal and the overlying molding powder, so that predefined parameters of both the molten metal and the molding powder may be detected as a function of the electromagnetic behavior of the electromagnetic open cavity. The electromagnetic behavior of the electromagnetic cavity is correlated with the depth of molding powder and the level of molten metal in the mold. In particular, if the curve of resonance of the electromagnetic cavity is detected, the depth of molding powder and the level of molten metal can be measured as a function of the bandwidth of said curve of resonance and the frequency of resonance of the cavity.
DESCRIPTION OF THE DRAWINGSIn the following, a description will be given with reference to the drawings of particular preferred embodiments; it has, however, to be noted that the present invention is not limited to the embodiments disclosed but that the embodiments disclosed only relate to particular examples of the present invention, the scope of which is defined by the appended claims. In this disclosure:
While the invention is described with reference to the embodiments as illustrated in the following detailed description as well as in the drawings, it should be understood that the following detailed description as well as the drawings are not intended to limit the present invention to the particular illustrative embodiments disclosed, but rather the described illustrative embodiments merely exemplify the various aspects of the present invention, the scope of which is defined by the appended claims.
The systems and methods described herein are particularly advantageous when used for detecting and/or measuring the depth of molding powder and the level of molten metal in a casting mold during a continuous casting process. For this reason, examples will be given in which corresponding methods and devices are applied to a continuous casting process and a continuous casting apparatus and are used for measuring the depth of molding powder and the level of molten metal in a casting mold. However, it has to be noted that the invention is not limited to the particular case of a continuous casting process carried out by means of a continuous casting apparatus comprising a casting mold, but can be used in any other situation in which predefined parameters of a molten or liquid metal in a container need to be measured and/or detected. In particular, it will become apparent from the following disclosure that these systems and methods are also applicable in other cases in which it is possible to realize an electromagnetic open cavity above the molten and/or liquid metal. It will also become apparent from the following disclosure that the present invention is applicable in all those cases in which the molten and/or liquid metal is contained in a container comprising an upper aperture so that an electromagnetic open cavity may be formed by placing a cover on the upper aperture, the electromagnetic open cavity being thus defined by the cover, in cooperation with the walls of the container and the molten metal in the container. In more detail, the features of the electromagnetic cavity relating the fact that the cavity is an “open” cavity is provided by means of apertures in the cover adapted to opportunely influence the electromagnetic behavior of the cavity. It has, therefore, to be understood that the systems and methods described herein are applicable for detecting and/or measuring all those parameters of a molten metal, for which a relationship may be established between those parameters and the electromagnetic behavior of the cavity and/or the electromagnetic features of electromagnetic signals exiting the cavity.
In
With reference now to
In the following, with reference to
In
For the purpose of receiving the electromagnetic signals emitted by the emitting device 21 of
During a continuous casting process, molten metal is introduced into the container or mold 1 through the nozzle 2 received inside the tube 12 of the measuring device 20 and the metal is discharged from the container 1 through the outlet aperture 1b. Moreover, molding powder is introduced into the container or mold 1, for instance through one or both of the apertures 14 of the main plate 11 of the cover 10. As it will be explained in more detail below, the measuring device 20 (comprising the main cover 10, the tube 12 and the emitting and receiving devices 21 and 22) defines, in combination with the walls of the container 1 above the molding powder 32 and the molten metal 31, an electromagnetic open cavity 35. The electromagnetic properties of the open cavity 35 may be used for detecting predefined parameters of both the molten metal 31 and the molding powder 32 contained in the container or mold 1. In particular, it has been established that a relationship always exists between the couple of the geometrical quantities 31a and 32a and the couple of the electromagnetic parameters defined by the frequency of resonance of the cavity 35 and the bandwidth of the frequency response. Accordingly, if the electromagnetic behavior of the cavity 35 is detected, it is also possible to compute and/or calculate the level of molten metal 31a and the depth of molding powder 32a in the container.
The equipment depicted in
The equipment depicted in
According to a preferred embodiment of the measuring method, consecutive electromagnetic signals of corresponding different frequencies are introduced into the cavity 35 according to a predefined time schedule. In particular, for the purpose of detecting the curve of resonance of the cavity, approximately 100 electromagnetic signals with corresponding different frequencies may be introduced into the cavity, with a time interval between two consecutive signals of about 1 microsecond.
The equipment depicted in
In
The electromagnetic behavior of the cavity 35 formed by the equipment depicted in
For the purpose of accurately detecting the behavior of the equipment depicted in
It appears from
The results of this inversion are depicted in
It results, therefore, from the above that detecting means with standard electronic equipment may be used for the purpose of appreciating variations in the level of molten metal and in the depth of molding powder within an accuracy of 1 mm.
In conclusion, the methods and systems described herein allow the measurement of the level of molten metal in the casting mold and the depth of molding powder floating over the molten metal. These two parameters may be measured simultaneously as a function of different properties of an electromagnetic open cavity formed inside the casting mold. It is possible, therefore, to overcome the most important drawbacks affecting those prior art measuring devices and methods that only allow the measuring of a single parameter comprehensive of both the molten metal and the molding powder flowing over the metal. Moreover, the measuring methods and devices described herein may be used with a large class of the casting systems known in the art. Furthermore, standard electronic equipment may be used for the purpose of measuring the level of molten metal and the depth of molding powder in a reliable manner, with an evident advantage concerning the overall costs of the equipment. Finally, the measuring methods and devices described herein do not need to be used in combination with devices and/or means for gauging both the depth of the molding powder and the level of molten metal in the casting mold.
Of course, it should be understood that a wide range of changes and modifications can be made to the embodiments described above without departing from the scope of the present invention. For instance, said changes and modifications may relate to the kind of emitting and receiving means used for introducing electrical signals into the cavity and for receiving the electrical signals exiting the cavity for the purpose of detecting the electromagnetic behavior and/or properties of the cavity.
Claims
1. A measuring device for measuring predefined parameters of a liquid metal in a container, the container comprising an inlet aperture through which the liquid metal is introduced into the container, wherein:
- the measuring device is adapted to be placed on said inlet aperture of said container so as to form, in combination with the container, an electromagnetic open cavity; and
- the measuring device comprises detecting means adapted to detect the electromagnetic behavior of the cavity so as to obtain said predefined parameters as a function of the electromagnetic behavior.
2. A measuring device as claimed in claim 1, wherein:
- the measuring device comprises an emitting device and a receiving device adapted to introduce electromagnetic input signals into the cavity and to receive output electromagnetic signals from the cavity, respectively, through corresponding input and output apertures of the container.
3. A measuring device as claimed in claim 2, wherein:
- the emitting device is adapted to introduce electromagnetic signals into the cavity within a predefined frequency range.
4. A measuring device as claimed in claim 3, wherein:
- the detecting means are coupled to said receiving device and are adapted to detect the curve of resonance of the cavity.
5. A measuring device as claimed in claim 4, wherein:
- the detecting means are adapted to detect the bandwidth of the curve of resonance.
6. A measuring device as claimed claim 4, wherein:
- the emitting device is adapted to introduce the electromagnetic signals into the cavity according to a predefined time schedule.
7. A measuring device as claimed claim 4, wherein:
- the device further comprises computing means adapted to calculate the parameters as a function of both the frequency of resonance of the cavity and the bandwidth of the curve of resonance.
8. A measuring device as claimed in claim 1, wherein:
- the device comprises a cover adapted to be placed on the inlet aperture of said container, with said cover comprising a main plate with at least one through aperture, the shape and dimension of which are adapted to influence the electromagnetic behavior of the cavity.
9. A measuring device as claimed in claim 8, wherein:
- the cover comprises at least two apertures of a rectangular shape.
10. A measuring device as claimed in claims 8, wherein:
- the device further comprises a tube firmly fixed to the main plate and disposed transversely with respect to the main plate.
11. A casting apparatus of the kind adapted to be used in a continuous casting process, the apparatus comprising a casting container with an inlet aperture for receiving liquid metal and an outlet aperture for discharging solidified metal, the container being adapted to contain a predefined amount of liquid metal, wherein:
- the casting apparatus is equipped with a measuring device on the inlet aperture of said container so as to form, in combination with the container, an electromagnetic open cavity; and
- the measuring device comprises detecting means adapted to detect the electromagnetic behavior of the cavity so as to obtain said predefined parameters as a function of the electromagnetic behavior.
12. A casting apparatus as claimed in claim 13, further comprising:
- means for introducing molding powder into the container;
- wherein the depth of molding powder in the container is detected as a function of the bandwidth of the frequency response and the resonance frequency of said cavity.
13. A casting apparatus as claimed in claim 12, further comprising means for adjusting the depth of molding powder in the container as a function of the depth of molding powder as detected.
14. A casting apparatus as claimed in claim 12, wherein the level of liquid metal in the container is detected as a function of the frequency of resonance and the bandwidth of the frequency response of the cavity.
15. A casting apparatus as claimed in claim 14, further comprising means for adjusting the level of liquid metal in the container as a function of the level as detected.
16. A measuring method for measuring predefined parameters of a liquid metal in a container, wherein the container comprises an inlet aperture through which the liquid metal is introduced into the container, the measuring method comprising:
- forming an electromagnetic open cavity above the liquid metal;
- detecting the electromagnetic behavior of the cavity; and
- obtaining the predefined parameters as a function of said electromagnetic behavior.
17. A measuring method as claimed in claim 16, further comprising:
- introducing electromagnetic input signals into the cavity; and
- receiving electromagnetic output signals from the cavity.
18. A measuring method as claimed in claim 17, wherein electromagnetic signals within a predefined frequency range are introduced into the cavity.
19. A measuring method as claimed in claim 18, further comprising detecting the curve of resonance of the cavity.
20. A measuring method as claimed in claim 19, further comprising detecting the bandwidth of the curve of resonance.
21. A measuring method as claimed in claim 19, wherein the electromagnetic signals are introduced into the cavity according to a predefined time schedule.
22. A measuring method as claimed in claim 19, further comprising calculating the parameters as a function of both the frequency of resonance of the cavity and the bandwidth of the curve of resonance.
23. A measuring method as claimed in claim 16, wherein:
- the container is a casting container adapted to be used in a continuous casting process and comprises an outlet aperture for discharging solidified metal; and
- the electromagnetic open cavity is defined by means of a cover, the cover comprising a main plate with at least one through aperture, the shape and dimension of which are adapted to influence the electromagnetic behavior of the cavity.
24. A measuring method as claimed in claim 23, wherein the main plate comprises at least two apertures of a rectangular shape.
25. A measuring method as claimed in claim 23, wherein the electromagnetic behavior of the cavity is further influenced by means of a tube firmly fixed to the main plate and disposed transversely with respect to the cover.
26. A measuring method as claimed in claim 23, wherein the container is further adapted to contain molding powder (32) above said liquid metal and in that the depth of molding powder in the container is detected as a function of the bandwidth of the frequency response and of the resonance frequency of the cavity.
27. A measuring method as claimed in claim 26, wherein the level of liquid metal in the container is detected as a function of the frequency of resonance and of the bandwidth of the frequency response of the cavity.
28. A continuous casting process comprising introducing liquid metal into a continuous casting mold and extracting solidified metal from said mold, said process further comprising measuring predefined parameters of the liquid metal in the mold, wherein the predefined parameters are measured in a method comprising:
- forming an electromagnetic open cavity above the liquid metal;
- detecting the electromagnetic behavior of the cavity; and
- obtaining the predefined parameters as a function of said electromagnetic behavior.
29. A process as claimed in claim 28, further comprising introducing molding powder into the mold, wherein the detected parameters comprise one or both of the level of liquid metal in the mold and the depth of molding powder.
30. A process as claimed in claim 29, wherein the depth of molding powder is detected as a function of the bandwidth of the curve of resonance and of the resonance frequency of the cavity.
31. A process as claimed in claim 30, wherein the process further comprises adjusting the depth of molding powder in the mold as a function of the depth of molding powder as detected.
32. A process as claimed in claim 30, wherein the level of liquid metal in the mold is detected as a function of the frequency of resonance and the bandwidth of the frequency response of the cavity.
33. A process as claimed in claim 32, further comprising the step of adjusting the level of liquid metal in the mold as a function of the level as detected.
Type: Application
Filed: Jun 2, 2006
Publication Date: Jan 25, 2007
Applicant: Fondazione Torino Wireless (Torino)
Inventors: Riccardo Tascone (Torino), Guiseppe Virone (Castelnuovo Don Bosco), Augusto Olivieri (Pianezza), Oscar Peverini (Buttigliera Alta)
Application Number: 11/446,474
International Classification: A47J 36/02 (20060101);